When the US imposed sanctions in December banning external contractors from working on Russia’s Nord Stream 2 gas pipeline to Germany, Washington hoped it had finally killed the controversial project stone dead. It was wrong. Gazprom, the Kremlin-controlled gas giant behind the project, called Washington’s bluff. By vowing to complete the pipeline by itself, it has presented an ultimatum the US has long sought to avoid: if you want to stop the pipeline, you need to place sanctions on us.

That is a gamble with potentially enormous consequences. Not only does Gazprom supply almost 40 percent of Europe’s gas, it has also raised €4.75bn to pay for Nord Stream 2 from European energy companies Shell, Engie, OMW, Uniper and Wintershall. Since it was announced in 2015, Nord Stream 2 has been mired in geopolitics, pitting Russia against the US and dividing the EU.

The pipeline would double the amount of gas piped directly from Russia to Germany and reduce the amount pumped through Soviet-era pipelines in Ukraine. As such, it has become a lightning rod for critics of Moscow who say Gazprom is seeking both to increase Europe’s dependence on Russian supplies and hurt Kyiv by depriving it of hefty transit fees.

The project weathered years of critical rhetoric, legal challenges and reluctance from Baltic countries whose permission was required to begin construction. Then US sanctions forced Swiss pipe-laying company Allseas to sail away from the project five months ago with 94 percent of it completed, and just 160km of pipe left to lay on the bottom of the Baltic Sea.

Gazprom now says it will bridge that gap –   in Danish territorial waters –   alone and get the pipeline ready to start operations in spring  2021. Whether it can actually do that looks set to depend on the Akademik Cherskiy, a pipe-layer that has spent most of the  past three months sailing halfway around the world.